To characterize hepatic CYP3A4 activity in HIV-positive subjects not receiving protease inhibitors, and to correlate ERMBT results prior to treatment with ritonavir or indinavir with subsequent trough serum concentrations of these two drugs in newly treated patients. A long term goal is that use of the ERMBT may allow for a reduced dosage of protease inhibitors in some patients without compromising efficacy. and that lower dosage will reduce toxicity, resulting in increased compliance and an increase in total duration of therapy.